The art of manufacturing a puffed dough-shape, particularly one which is sold in an assortment of characters such as alphabets, numerals or related but dissimilar shaped pieces such as animal forms for novelty purposes has relied upon the art of gun-puffing a partially cooked dough piece, viz. U.S. Pat. Nos. 2,954,295 and 2,954,296, issued Sept. 27, 1960, both entitled Process for Preparing Puffed Cereal Product, to Clausi et al. The limitations of gun puffing are such, however, that uniformity of the puffed dough pieces leaves much to be desired and yield of faithfully shaped expanded particles is less than would be preferred for optimal utilization of raw materials. Furthermore, from the standpoints of safety, sanitation and simplicity of equipment, it would be preferable if means other than a gun-puffer were employed for manufacturing novel shaped expanded dough masses.
One avenue for making a shaped dough piece which has been used commercially is a cooker extruder expander wherein a moist cereal dough is subjected to controlled heat and mechanical work to convert the starch content thereof into a partially gelatinized condition, at least, and cause the dough to pass an extruding die whereby the dough moves from a confined zone of high pressure to an unconfined zone of much lower, say, atmospheric pressure and the individual dough extrudate when it is simultaneously so-exposed undergoes rapid expansion.
Whereas such cooker expanders have enjoyed utility in manufacturing such products for sale as dry, ready-to-eat breakfast cereal products and snacks, they are limited in their versatility. It is sometimes preferable in marketing such products that they be in assorted shapes and that they not only be uniformly expanded but also that they be of a consistent size relative to one another. Providing such an assortment calls for employing a die assembly having a plurality of different shapes be they alphabetical, numerical or the like. Unfortunately, by reason of varying flow characteristics of the dough mass passing through differing shaping die orifices, there is a multiplicity of hydraulic flow patterns which must be reconciled if each of the cooked dough masses are to pass their respective extruding die in a uniform manner that results in a substantially comparable linear velocity for each moiety of cereal dough. The problem becomes manifest when, with varying flows, a rotating cutting knife will subdivide varying depths from the extrudate and result in eccentricities of product form as well as a loss of intended shape definition.
Accordingly, it is among the objects of the present invention to provide a cooker extruder expander die assembly and method of expanding an assortment of individual dough moieties whereby, despite their varying character as shaped, they are caused to issue from a confined zone of high pressure to a less confined zone of lower pressure and become expanded uniformly, said issuance being caused by the dough masses moving at a substantially comparable linear velocity with respect to the longitudinal axis of the extruder.